A rat-catcher is a person who kills or captures rats as a professional form of pest control. Keeping the rat population under control was practiced in Europe to prevent the spread of diseases, most notoriously the Black Death, and to prevent damage to food supplies. In modern developed countries, such a professional is otherwise known as a pest control operative or pest exterminator.

Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus Rattus. Other rat genera include Neotoma, Bandicota and Dipodomys.